sedimentary

Mookaite Jasper

Radiolarite (Chert/Jasper variety), formula SiO2

Hardness: 6.5-7.0 (Mohs scale); Color: Earthy tones of yellow, red, burgundy, and brown; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9

Hardness: 6
Color: Earthy tones of yellow, red, burgundy, and brown
Luster: Vitreous to waxy

Identified March 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the silicification of the radiolarian siltstone Windalia Radiolarite. This deposit was created by the skeletal remains of radiolaria (tiny organisms) settling in a shallow sea during the Lower Cretaceous (~145–100 million years ago).

Uses & applications

Primarily used in jewelry (cabochons, pendants), ornamental carvings, and as a popular semi-precious gemstone for mineral collectors and lapidary artists.

Geological facts

Mookaite is found only in one place in the world: Mooka Station in the Kennedy Ranges near Gascoyne Junction, Western Australia. The term 'Mooka' is derived from a local Aboriginal word meaning 'running waters'.

Field identification & locations

Field identification: Look for its signature vibrant, opaque, 'paint-like' bands of earthy colors and its extreme hardness; it will easily scratch glass. Found in creek beds and outcrop deposits in the Kennedy Ranges.

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